Aerosol dispensers are well known in the art. Aerosol dispensers typically comprise an outer container which acts as a frame for the remaining components and as a pressure vessel for propellant and product contained therein. Outer containers made of metal are well known in the art. However, metal containers can be undesirable due to high cost and limited recyclability. Attempts to use plastic have occurred in the art. Relevant attempts in the art to employ plastic in aerosol dispensers are found in U.S. Pat. Nos. 2,863,699; 3,333,743; 9,296,550 and 2009/0014679.
The outer containers are typically, but not necessarily, cylindrical. The outer container may comprise a bottom for resting on horizontal surfaces such as shelves, countertops, tables etc. The bottom of the outer container may comprise a re-entrant portion as shown in U.S. Pat. No. 3,403,804 or base cup as shown in U.S. Pat. No. 9,061,795. Sidewalls defining the shape of the outer container extend upwardly from the bottom to an open top.
The open top defines a neck for receiving additional components of the aerosol dispenser. The industry has generally settled upon a nominal neck diameter of 2.54 cm, for standardization of components among various manufacturers, although smaller diameters, such as 20 mm, are also used. Various neck shapes are shown in U.S. Pat. Nos. 6,019,252; 7,303,087; 7,028,866 and 7,279,207.
Typically a valve cup is inserted into the neck. The valve cup is sealed against the neck to prevent the escape of the propellant and loss of pressurization, such as described in U.S. Pat. Nos. 8,074,847; 8,096,327; 8,844,765 and 8,869,842. The valve cup holds the valve components which are movable in relationship to the balance of the aerosol dispenser. Suitable valves are shown in commonly assigned U.S. Pat. Nos. 8,511,522 and 9,132,955.
Aerosol dispensers, having a valve cup and movable valve components, may comprise different embodiments for holding, storing, and dispensing product used by the consumer. In one embodiment, the product and propellant are intermixed. When the user actuates the valve, the product and propellant are dispensed together. This embodiment may utilize a dip tube. The dip tube takes the product and propellant mixture from the bottom of the outer container. This embodiment may be used, for example, to dispense shaving cream foams.
Or, a collapsible, flexible bag may be sealed to the opening on the underside of the valve cup or may be placed between the valve cup and the container. This bag limits or even prevents intermixing of the contents of the bag and the components outside of the bag. Thus, product may be contained in the bag. Propellant may be disposed between the outside of the bag and the inside of the outer container. Upon actuation of the valve, a flow path out of the bag is created. This embodiment is commonly called a bag on valve and may be used, for example, in dispensing shaving cream gels. An aerosol container having a bag therein may be made from a dual layer preform, having plural layers disposed one inside the other. Relevant attempts in the art include U.S. Pat. Nos. 3,450,254; 4,330,066; 6,254,820; RE 30093 E; WO 9108099 and US 2011/0248035 A1.
But aerosol container having a bag on valve or dip tube configuration are not well suited to dispense high viscosity products. High viscosity products occur in many forms, such as mousse, toothpaste, caulk, shave gel, body lotion, shampoo, antiperspirant, etc. Pistons as disclosed in U.S. Pat. Nos. 3,433,134; 3,827,607; 4,234,108; 5,127,556; and 8,245,888 may be used if high viscosity products are dispensed.
If a valve is to be assembled into an aerosol, typically the valve cup is crimped on. But this operation is expensive and cannot be used with a plastic valve cup. Accordingly an interlock, may be used to attach a valve assembly to a valve cup, particularly a plastic valve assembly and plastic valve cup are used. A suitable valve may be according to U.S. Pat. No. 9,132,955. Suitable interlocks include bayonet fittings and threads. Yet other attempts in the art include U.S. Pat. Nos. 3,718,165; 3,804,759; 8,985,398; 9,132,952 and 9,221,596.
The interlock, particularly threads, may be internal or external to the valve cup. Internal threads have the advantage of less area, and proportionately greater blowout force resistance than, external threads. An internally fitted valve cup makes it more difficult to remove the valve therefrom, providing increased safety.
But sealing product in an aerosol having the valve attached to the valve cup via threads or a bayonet fitting presents other problems. For example, sealing is difficult as threads and bayonet fittings are usually not tight enough to prevent loss of pressure, yet loose enough for ease of assembly.
Accordingly, this application is directed to solving the problem of sealing a plastic valve to a plastic valve cup in an aerosol container.